Computech Systems RaceAir Pro - Gear Ratio

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Press the SAMPLE key and allow the weather analyzer to stabilize on the = Sampled Wthr =
screen. Press T-STOP, then 1 Car #228 to start this program.
T-Stop Display Example:
=T-Stop Car #228
Fuel= Methanol (Fuel selected)
Old Tmr? 1.540 (Enter timer setting for reference run)
Old Corr? 0.9878 (Enter correction factor for reference run)
Old ET? 8.914 (Enter ET for reference run)
New Corr? 1.0004 (Auto transferred new correction factor)
New ET? 8.900 (Enter desired new ET)
New Tmr= 1.457 (New timer setting to run desired ET)
Gear Ratio, Drag.
This program will calculate the necessary gear ratio to obtain the desired finish line engine RPM
while accounting for tire size and torque converter slip. This program works for 1/8 mile as well
as 1/4 mile drag racing.
Press DRAG FORMULAS, then Gear Ratio to start this program.
Display Example:
== Est. ET/MPH==
Tire…
…Circum? 106.0 (Enter tire circumference inches - not diameter)
Trap MPH? 154.00 (Enter desired finish line MPH)
Trap RPM? 7800 (Enter desired finish line engine RPM)
Conv Slip? 800 (Enter estimated torque converter slip RPM)
Gear Ratio= 4.56 (Calculated gear ratio)
Engine Trap RPM, Drag.
This program calculates the estimated finish line engine RPM. The variables considered are: ring
and pinion gear ratio, tire circumference (roll out), finish line MPH, and estimated torque converter
or clutch slippage at the finish line. This program works for both 1/8 mile and 1/4 mile tracks.
Press DRAG FORMULAS, then Trap RPM to start this program.
Display Example:
== Est. ET/MPH==
Tire…
…Circum? 106.0 (Enter tire circumference inches - not diameter)
Trap MPH? 154.00 (Enter desired finish line MPH)
Gear Ratio? 4.56 (Enter rear end gear ratio)
Conv Slip? 800 (Enter estimated torque converter slip RPM)
Trap RPM= 7800 (Calculated finish line engine RPM)